Cushioned carpeted floor covering article comprising at least one integrated rubber protrusion

ABSTRACT

This invention relates to a cushioned floor covering article wherein the mat includes a tufted carpet placed on the top side of a foam rubber sheet and at least one foam rubber protrusion integrated within at least a portion of the bottom side of the foam rubber sheet. Such an article provides effective removal of moisture, dirt, and debris from the footwear of pedestrians through the utilization of a carpet pile component. Furthermore, the utilization of a foam rubber backing also allows for either periodic heavy duty industrial-scale laundering in such standard washing machines or periodic washing and drying in standard in-home machines, both without appreciably damaging the inventive floor covering article, such as a floor mat. Additionally, the presence of integrated foam rubber protrusions within the mat structure provides an effective cushioning effect for pedestrian comfort as well as a means to prevent slippage of the article from its contacted surface. A method of producing such an inventive cushioned floor covering article is also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of application 09/374,321, filed onAug. 13, 1999, now U.S. Pat. No. 6,296,919.

FIELD OF THE INVENTION

This invention relates to a cushioned floor covering article wherein themat includes a tufted carpet placed on the top side of a foam rubbersheet and at least one foam rubber protrusion integrated within at leasta portion of the bottom side of the foam rubber sheet. Such an articleprovides effective removal of moisture, dirt, and debris from thefootwear of pedestrians through the utilization of a carpet pilecomponent. Furthermore, the utilization of a foam rubber backing alsoallows for either periodic heavy duty industrial-scale laundering insuch standard washing machines or periodic washing and drying instandard in-home machines, both without appreciably damaging theinventive floor covering article, such as a floor mat. Additionally, thepresence of integrated foam rubber protrusions within the mat structureprovides an effective cushioning effect for pedestrian comfort as wellas a means to prevent slippage of the article from its contactedsurface. A method of producing such an inventive cushioned floorcovering article is also provided.

DISCUSSION OF THE PRIOR ART

All U.S. patent cited herein are hereby fully incorporated by reference.

Floor mats have long been utilized to facilitate the cleaning of thebottoms of people's shoes, particularly in areas of high pedestriantraffic such as doorways. Moisture, dirt, and debris from out of doorseasily adhere to such footwear, particularly in inclement weather andparticularly in areas of grass or mud or the like. Such unwanted andpotentially floor staining or dirtying articles need to be removed froma person's footwear prior to entry indoors. As will be appreciated, suchoutdoor mats by their nature must undergo frequent repeated washings anddryings so as to remove the dirt and debris deposited thereon duringuse. These mats are generally rented from service entities whichretrieve the soiled mats from the user and provide clean replacementmats on a frequent basis. The soiled mats are thereafter cleaned anddried in an industrial laundering process (such as within rotary washingand drying machines, for example) and then sent to another user inreplacement of newly soiled mats. Furthermore, it is generally necessaryfrom a health standpoint to produce floor coverings on which persons maystand for appreciable amounts of time which will provide comfort to suchpersons to substantially lower the potential for fatigue of such personsby reducing the stress on feet and leg joints through cushioning.

Typical carpeted dust control mats comprise solid and/or foam rubberbacking sheets which must be cleated in some manner to prevent slippageof the mat from its designated area. Such cleats are formed during avulcanization step and have required a time-consuming procedure ofplacing the green (unvulcanized) rubber sheet on a molded silicone padand then removing the same after vulcanization. Also, the thicknesses ofsuch dust control rubber backing sheets are generally quite low and thuspermit the placement of a pedestrian's foot relatively close to thecovered floor or ground when he steps on such a mat. As a result, andparticularly if the covered area is hard, the mat does not appreciablycushion the pedestrian's foot. With a general shift toward providingprotection to pedestrians, particularly outside entryways of stores,where a cushioned, non-slip dust control mat will provide a safe,comfortable floor covering on which a customer may clean his footwear,and workplaces, where a person may be required to be mobile for anappreciable amount of time during the workday and thus a non-slip,cushioned floor covering provides a certain degree of safety to a user,there is a recognized need to provide non-slip floor and/or groundcoverings which can potentially reduce the stress of a pedestrian's legand foot joints through the benefit of cushioning characteristics. Therehave been a few advancements within the prior art for providingcushioning within dust control mats, such as U.S. Pat. No. 5,645,914 toHorowitz. Generally, such cushioning benefits are provided in eitheronly all-rubber mats, as in U.S. Pat. No. 3,016,317 to Brunner, orsolely provide such cushioning benefits within or on the top side of themat, as in U.S. Pat. No. 4,262,048 to Mitchell. Also, cleated backingshave been produced in the past to provide non-slip characteristics, suchas in U.S. Pat. No. 4,741,065 to Parkins. Such mats do not also providecushioning characteristics with the same non-slip components, however.As such, there still exists a need to reduce cost for producing overalldust control mat products through a process wherein the cushioningcharacteristics are simultaneously provided by the same non-slipmechanism. To date, the prior art has neither taught nor fairlysuggested such a combination of elements in a cushioned carpeted floorcovering article.

DESCRIPTION OF THE INVENTION

It is thus an object of this invention to provide a non-slip, cushioned,anti-fatigue carpeted floor covering article which permits cleaning of apedestrian's footwear. Furthermore, it is an object of the invention toprovide a carpeted floor covering article for which the portion whichprovides the cushioning characteristics simultaneously provides non-slipbenefits. An additional object of this invention is to provide anon-slip, cushioned, antifatigue carpeted floor covering article inwhich the cushioning aspects are provided by at least one integratedrubber protrusion produced during the necessary vulcanization process.Still a further object of the invention is to provide a non-slip,cushioned carpeted floor covering article which possesses sufficientflexibility to withstand periodical laundering in industrial washing anddrying machines. Yet another object of this invention is to provide afloor covering article which can substantially reduce a person's fatigueafter standing on such an article for appreciable periods of time ascompared with other standard floor covering articles.

Accordingly, this invention encompasses a cushioned floor coveringarticle comprising

a carrier fabric;

a pile material tufted into the carrier fabric which forms a pilesurface on one side of the carrier fabric; and

a vulcanized expanded backing sheet of rubber attached to the other sideof the carrier fabric, wherein at least one protrusion integrated withinsaid backing sheet is present on the side of the backing opposite theside to which the carrier fabric is attached. Also, this inventionencompasses a method of forming a cushioned floor covering articlecomprising the steps of

(a) placing a sheet of rubber over a die having at least a first andsecond side, wherein said rubber optionally comprises a blowing agent toform a closed-cell foam rubber structure upon vulcanization, whereinsaid die has portions thereof removed to allow for the entry of moltenrubber, and wherein said die is comprised of a material which canwithstand vulcanization temperatures and pressures;

(b) tufting a pile material into a carrier fabric to form a tufted pilesurface extending from one side of the carrier fabric;

(c) laying the carrier fabric with tufted pile onto the rubber sheet ofstep “a”;

(d) optionally, placing solid rubber reinforcing strips around at leastone of the border edges of the rubber sheet; and

(e) subjecting the composite comprising the rubber sheet, the die, thecarrier fabric, the carpet pile, and the optional reinforcing strips tovulcanization temperatures and pressures to (1) attach the rubber sheetto the side of the carrier fabric from which the pile surface does notextend, and (2) to form rubber protrusions through the removed portionsof the die.

The inventive dust control mat generally comprises any type of standardcarpet pile fibers tufted through any standard type of carrier fabric.Such carpet fibers may be natural or synthetic, including, withoutlimitation, cotton, ramie, wool, polyester, nylon, polypropylene, andthe like, as well as blends of such fibers (all as merely examples). Thefibers may be coarse or fine in structure as well. Such fiber structuresare represented in dust control mats within U.S. Pat. No. 1,008,618,toSkowronski et al., U.S. Pat. No. 4,045,605,to Breens et al., and U.S.Pat. No. 4,353,944, to Tarui, U.S. Pat. Nos. 4,820,566 and 5,055,333,both to Heine et al., as well as within French Patent No. 1,211,755,assigned to Cosyntex (S.A.), and PCT Application 95/30040,assigned toKleen-Tex Industries, Inc. Of particular interest in this invention,however, are 100% solution dyed nylon fibers. Such pile fibers providethe best pile surface for overprinting with different dyes in order toprovide the most aesthetically pleasing colorations and shades on thefloor mat pile surface. The carrier fabric may thus be of anyconstruction, such as woven, non-woven, knit, and the like. Preferably,a woven or non-woven substrate is utilized. The carpet pile is tuftedthrough the carrier fabric in a standard tufting process for furtherplacement on and attachment during vulcanization to the top side of therubber backing sheet.

The carpet fibers may be colored or dyed through any acceptable methodso as to produce aesthetically pleasing designs within the carpet pileportion of the inventive mat. Of particular importance, however, is theutilization of an overprinting procedure of 100% solution dyed nylonfibers. Such nylon is acid-dyeable and available from Cookson Fibers. Asnoted above, such pile fibers allow for the most pleasing andlong-lasting colorations and shades of color to be applied and retainedon the pile surface through the utilization of acid dyes. With suchfibers, any design or configuration may be produced (as well as logos,pictures, and the like) on the pile surface, again in order to provide along-lasting aesthetically pleasing floor mat for the consumer.Furthermore, the inventive article itself can be made in any shape, withrectangular or square configurations being preferred.

In actuality, the attachment of the rubber sheet component to the carpetpile fibers may be accomplished either during the actual vulcanizationstep, as taught in Nagahama, for example, above, or through the use ofan adhesive layer, preferably a polyolefin adhesive, between the carpetpile and the rubber sheet, as disclosed in copending U.S. patentapplication Ser. No. 08/732,866, to Kerr, hereby entirely incorporatedby reference, or any other like procedure.

The rubber backing sheet may be comprised of any standard rubbercomposition, including, but not limited to, acrylonitrile-butadienerubber (NBR), styrene-butadiene rubber (SBR), ethylene--propylene-dienecomonomer rubber (EPDM), carboxylated NBR, carboxylated SBR, chlorinatedrubber, silicon-containing rubber, and the like. For cost purposes, thepreferred rubbers are NBR, SBR, EPDM and blends thereof.

The rubber composition may be of solid or foam construction or there maybe layers of both present on the inventive mat. Preferably, the majorityof the rubber composition within the backing sheet is of foamconstruction (which requires the presence of a blowing agent to formclosed-cell structures within the rubber upon vulcanization, such as inU.S. Pat. No. 5,305.,565 to Nagahama et al.). The target thickness forsuch a rubber sheet is from about 5 to about 500 mils, preferably fromabout 25 to about 400 mils, more preferably from about 40 to about 250mils, and most preferably from about 75 to about 200 mils.

Floor mats and other like floor covering articles have exhibited generalproblems arising from frequent washings and harsh environments of use.First, the energy required to wash and dry a typical floor mat issignificant due to the overall mass of the mats. This overall mass ismade up of the mass of the mat pile, the mass of the carrier fabric intowhich the mat pile is tufted, and most significantly, the mass of therubber backing sheet which is integrated to the carrier fabric underheat and pressure. As will be appreciated, a reduction in the overallmass of the floor mat will result in a reduced energy requirement inwashing and drying the mat. Moreover, a relative reduction in the massof the rubber backing sheet (i.e. the heaviest component) will providethe most substantial benefit. Thus, the utilization of a lighter weightrubber composition, such as foam rubber, in at least a portion of thedust control mat of the present invention includes a rubber backingsheet which may possess a specific gravity which is approximately 25-35percent less then the solid rubber sheets of typical prior floor mats.Accordingly, a foam rubber is preferable, though not required, as therubber structure of the inventive mat's rubber backing sheet. Thislighter weight thus translates into a reduced possibility of the matharming either the washing or drying machine in which the mat iscleaned, or the mat being harmed itself during such rigorous procedures.Although the inventive floor mat must withstand the rigors of industrialmachine washing, hand washing and any other manner of cleaning may alsobe utilized. Overall, the inventive floor mat provides an article whichwill retain its aesthetically pleasing characteristics over a longperiod of time and which thereby translates into reduced costs for theconsumer.

Solid rubber reinforcement strips may also be added around the bordersof the mat, either by hand or in an in-line process, such as in PatentCooperation Treaty application Ser. No. 96/38298, to Milliken ResearchCorporation. Such strips must either possess roughly the same shrinkagerate factor as the carpet pile substrate and the foam rubber backingsheet or they must possess roughly the same modulus strength of thesolid rubber backing sheet, all in order to ensure the probability ofrippling (or curling) of the mat will be minimal. Such strips may becomprised of any type of butadiene rubber, such asacrylonitrile-butadiene (NBR) or styrene-butadiene (SBR), orcarboxylated derivatives of such butadienes, merely as examples.Preferably, the strips are comprised of NBR as carboxylated NBR is costprohibitive. Such strips can be of any general width and as long as thespecific side upon which they are attached on the backing sheet. Thetarget thickness for such strips second layer is from about 2 to about50 mils, preferably from about 4 to about 40 mils, more preferably fromabout 5 to about 35 mils, and most preferably from about 5 to about 25mils. Furthermore, if such strips are applied, they should be placed ontop of the backing sheet prior to the placement of the carpet pile ifthe width of such strips, as measured from the border of the sheet, isgreater then the width of the area from the border to the carpet pile,in order to permit overlap of the strips and the carpet pile whilesimultaneously permitting adhesion of the strips to the sheet.

Furthermore, a significant problem exists within this field concerningthe deterioration of the carbon-carbon double bonds in the matrix of therubber backing sheet due to the exposure of the sheets to an oxidizingenvironment during use and cleaning. Specifically, the exposure of themats to oxidizing agents during the washing and drying process tends tocleave the carbon-carbon double bonds of the rubber sheet therebysubstantially embrittling the rubber which leads to cracking under thestress of use. In addition to the laundering process, the exposure ofthe mats to oxygen and ozone, either atmospheric or generated, duringstorage and use leads to cracking over time. The mat of the presentinvention may thus include an ozone-resistance additive, such asethylene-propylene-diene monomer rubber (EPDM), as taught within U.S.Pat. No. 5,902,662,to Kerr, which provides enhanced protection to therubber backing sheet against oxygen in order to substantially prolongthe useful life of the mat. Such an additive also appears to provide areduction in staining ability of such rubber backed mats upon contactwith various surfaces, such as concrete, wood, and a handler's skin,just to name a few, as discussed in U.S. patent application Ser. No.09/113,842 to Rockwell, Jr.

U.S. Pat. No. 5,305,565, to Nagahama et al., previously entirelyincorporated by reference, shows the usual manner of producing floormats comprising carpet pile fibers, a carpet pile substrate, and arubber backing sheet. This reference, however, makes no mention as tothe production of at least one integrated rubber protrusion from theside of the backing sheet opposite the carpet pile component. The term“integrated rubber protrusion” is intended to encompass any type ofprotrusion from the rubber backing sheet which is formed from the samebacking sheet composition and is not detached from the resultant backingsheet after vulcanization. Thus, such a protrusion would be producedthrough the flowing of the rubber composition during vulcanization andallowing molten rubber to form around a die mold in a position in whichit remains until it cures and sets. The shape of such a protrusion isvirtually limitless, and may be of any size. Furthermore, it is possibleto construct sheet wherein the body of the structure comprises a blowingagent (to produce a foam rubber) and a second layer of solid rubbercovers the body portion. In such a manner, the protrusions could beformed with a core of foam rubber and a cap of solid rubber (uponvulcanization through a die-mold, for example). As such, preferably theprotrusion or protrusions are formed from all foam rubber (whichprovides better cushioning). The separate protrusions thus providediscrete areas of relaxed stress within the inventive mat which thusprovides a cushioning effect to a pedestrian, greater than for anoverall flat foam rubber structure.

As noted previously, since the protrusion or protrusions are bothlocated on the bottom side of the backing sheet and extend from thesheet itself, such a protrusion or protrusions provides a non-slipcharacter to the overall mat structure. Since the length of theprotrusions cannot be greater than the depth of the backing sheet itself(since it is vulcanized on a solid surface, the resultant protrusionsare formed through the embedding of the die-mold within the backingsheet during vulcanization; removed portions of the die provide theholes in which the protrusions are ultimately formed from molten, thencooled rubber), such protrusions, being separate from the body of themat through some type of shaft (again of any size and shape), form“feet” which can grip the surface on which the mat is placed and createdifficulty in moving the mat through a pushing motion parallel to such asurface. Thus, the protrusions also provide a non-slip characteristic tothe inventive mat. Again, as noted above, there has been no teaching orfair suggestion of such an advantage (in cost, at least) for anaesthetically pleasing carpeted dust control mat.

With regard to the die, it may be constructed of any material which canwithstand vulcanization temperatures (i.e., between about 250° F. andabout 350° F.) and pressures (i.e., between about 15 psi and 50 psi,generally). Thus, any metal may be utilized, certain plastics, such asTeflon®, for example, silicon molds, and the like. Preferably, the dieis made of steel, is generally square or rectangular in shape (althoughany shape may be utilized), and comprises holes throughout to ultimatelyform the desired protrusions. Preferably, such holes are circular inshape (at the die surface) and cylindrical as well (i.e., circular onboth surfaces with the same shape throughout the die from one surface tothe other). Furthermore, such a die may also be utilized in an in-lineprocess wherein there is no need to hand place the backing sheet overthe die itself. The preferred procedure is outlined more particularlybelow.

The inventive mat provides a long-lasting non-slip, cushioned carpetedarticle which provides comfort to users as well as significantly reducedchances of slipping, all in a one-step procedure. All of this translatesinto reduced cost for the consumer as costs to produce are lower andpossible medical and insurance costs may also be reduced with theutilization of such specific mats which also work to remove dirt andmoisture from pedestrians' footwear.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a floor mat manufacturingmachine with the inventive process ongoing.

FIG. 2 is an aerial view of the components of the inventive dust controlmat placed together prior to vulcanization.

FIG. 3 is an aerial view of the preferred die.

FIG. 4 is a cross-sectional view of the inventive dust control mat aftervulcanization.

DETAILED DESCRIPTION OF THE DRAWINGS

While the invention will be described in connection with certainpreferred embodiments and practices, it is to be understood that it isnot intended to in any way limit the invention to such embodiments andpractices. On the contrary, it is intended to cover all alternatives,modifications and equivalents as may be included within the spirit andscope of the invention as defined by the appended claims.

Turning now to the drawings wherein like elements are designated by likereference numerals in the various views, FIG. 1 shows a floor matmanufacturing machine 10 for producing the inventive dust control mat24.The machine 10 comprises a conveyor belt 11 which carries the matcomponents 14, 16, 18, 20 from an initial placement area 12 (where eachcomponent is placed in sequence) through a vulcanization chamber 22 andto a removal area 26. Thus, a die 14 is first placed on the belt 11. Ontop of the die 14 is then placed a rubber sheet 16 which includes ablowing agent (preferably), followed by solid rubber strips 18 placedaround the perimeter of the first rubber sheet 16.These strips are thesame length as each of the sides of the first rubber sheet 16 and areeach preferably about 2 to 4 inches in width. The first number sheet 16has a thickness of about 40 mils and the solid rubber strips 18, beingmuch thinner, has a thickness of about 2.5 mils. To this die/rubbercomposite 13 is then placed a carpet pile through a carrier fabric 20.The resultant combination is then moved into the vulcanization chamber22, which includes a heated press (not illustrated) to subject the matcomponents to a temperature of about 290° C. and a pressure of about 30psi. After vulcanization, the finished mat 24 is allowed to cool and canthen be removed from the die 14. This entire procedure or only portionsthereof may be performed in an in-line process, such as in U.S. Pat.Nos. 5,928,446 and 5,932,317, both to Kerr et al.

FIG. 2 gives a greater detailed view of the die/rubber composite 13 aswell as a cut-away view of the carpet pile 20 added on top of thecomposite 13. On top of the die 14 is placed the first rubber sheet 16(including a blowing agent to form a foam rubber ultimately). The solidrubber strips 18 are placed around the perimeter of the first rubbersheet 16,leaving some overlap of the carpet pile 20 once that componentis placed on top of the first rubber sheet 16 and a portion of therubber strips 18.

The preferred die 14 is more thoroughly depicted in FIG. 3. The die ispreferably about 2 inches tall and made of steel. Any material may beused for this die 14 as long as it can withstand vulcanizationtemperatures and pressures without distorting its shape or permanentlyadhering to the mat product (24 of FIG. 1) (such as, as merely examples,other metals like titanium, aluminum, and the like; fibers, such aspolyaramid structures, and the like; silicon molds; and ceramics). Thepreferred die 14 comprises a plurality of cut-outs 28 which are, againpreferably, circular in shape, and thus cylindrical in configuration,having a diameter of about 1 inch and a depth of 2 inches. It is throughthese holes 28 that the rubber composition of the first rubber sheet (16of FIG. 2) is pressed to ultimately form the desired protrusions (34 ofFIG. 4) on the bottom side of the preferred mat (24 of FIG. 1).

FIG. 4 thus shows a cross-section of a portion of the finished inventivedust control mat 24. Protrusions 34 have been formed comprising foamrubber from the first rubber sheet 16. The rubber strip 18 has beenadhered to the first rubber sheet 16 and the carpet pile component20,comprised of cut pile fibers 32 and a carrier fabric 30,have becomeadhered to both the first rubber sheet 16 and the rubber strip 18.Theresultant preferred protrusions 34 are each about 1 inch in diameter andabout 2 inches in length.

DETAILED DESCRIPTION OF THE INVENTION

As previously indicated, in the preferred embodiment of the presentinvention the base material for the first rubber backing sheet isacrylonitrile-butadiene rubber (NBR) or styrene-butadiene rubber (SBR).Other materials which may also be used include, by way of example,hydrogenated NBR, carboxylated NBR, EPDM, and generally any otherstandard types of rubbers which may be formed in a foam state. As willbe appreciated, the use of NBR or SBR is desirable from a costperspective.

The present invention makes use of the addition of chemical blowingagents to the rubber materials ultimately yielding a lighter rubbersheet. Specifically, in the preferred embodiment, the rubber backingsheet of the present invention comprises either NBR or SBR or both mixedwith a blowing agent. The rubber/blowing agent mixture is thereaftercalendared as a solid sheet of unvulcanized material which is used inthe manufacture of the floor covering article in the process asdescribed above. In practice, the raw NBR is believed to be availablefrom Miles Inc. Rubber Division in Akron, Ohio. The SBR may be purchasedfrom Goodyear Tire and Rubber Company in Akron, Ohio. EPDM may also beadded in a preferred embodiment to provide ozone resistance.

In the preferred practice of the present invention, a masterbatch of thepolymer components is first prepared by mixing the base rubber (eitherNBR or SBR) with the additive ozone resistant polymer (EPDM) in thedesired ratio along with various stabilizers and processing agents.Exemplary compositions of the masterbatch for various additive ratioswherein EPDM is mixed with NBR are provided in Table 1A for ratios ofNBR to the additive polymer of 9.0 (Column a), 2.3 (Column b) and 1.2(Column c).

TABLE 1A PARTS BY WEIGHT MATERIAL a b c Rubber (NBR) 40 25 50 AdditiveRubber (EPDM) 60 75 50 Plasticizer 10 5 15 Stabilizer 2 2 2 ProcessingAid 1.75 1.75 1.75 Antioxidant 1.2 1.2 1.2

In the preferred practice the plasticizer which is used isdiisononylphthalate. The stabilizer is trinonylphenolphosphate availablefrom Uniroyal Chemical under the trade designation Polyguard™. Theprocessing aid is purchased from the R. T. Vanderbilt Company in NorwalkConn. under the trade designation Vanfree™ AP-2. The antioxidant ispurchased from Uniroyal Chemical under the trade designation Octamine™.

Following the mixing of the masterbatch, curative agents are added in asecond stage mixing process for formation of the raw rubber compoundwhich forms the backing sheet of the floor covering article of thepresent invention. An exemplary composition of the raw rubber compoundformed in this second stage mixing process is provided in Table 1B.

TABLE 1B MATERIAL PARTS BY WEIGHT Masterbatch Blend 100 Sulfur 1.25Stearic Acid 1 Carbon Black N-550 40 Vulkacit Thiaram MS (TMTM) 0.5 ZincOxide 5 Blowing Agent 2.5

Exemplary compositions of the masterbatch for various additive ratios ofSBR to EPDM are provided in Table 2A in a manner similar to that ofTable 1A.

TABLE 2A PARTS BY WEIGHT MATERIAL a b c Rubber (SBR) 40 25 50 AdditivePolymer (EPDM) 60 75 50 Stearic Acid  1  1  1 Sunolite 240  2  2  2 ZincOxide  5  5  5 Carbon Black N-550 30 30 30 Carbon Black N-224 60 60 60Calcium Carbonate 35 35 35 Talc 30 30 30 Supar 2280 80 80 80

After mixing of the SBR masterbatch, curative agents are preferablyadded in a second stage mixing process for formation of the raw rubbercompound which forms the backing sheet of the floor covering article ofthe present invention. An exemplary composition of the raw rubbercompound formed in this second stage mixing process is provided in Table2B.

TABLE 2B MATERIAL PARTS BY WEIGHT Masterbatch Blend 100 Sulfur 2 MethylZimate 1.25 Butyl Zimate 1.25 Dibutyl Thiurea 2.50 TelluriumDiethyldithiocarbanate 1 Blowing Agent 2.0

As previously indicated and shown above, the rubber backing sheetincludes a blowing agent to effectuate the formation of closed gas cellsin the rubber during vulcanization. The blowing agent which ispreferably used is a nitrogen compound organic type agent which isstable at normal storage and mixing temperatures but which undergoescontrollable gas evolution at reasonably well defined decompositiontemperatures. By way of example only and not limitation, blowing agentswhich may be used include: azodicarbonamide (Celogen™ AZ-type blowingagents) available from Uniroyal Chemical Inc. in Middlebury Connecticutand modified azodicarbonamide available from Miles Chemical in Akron,Ohio under the trade designation Porofor™ ADC-K.

It has been found that the addition of such blowing agents at a level ofbetween about 1 and about 5 parts by weight in the raw rubbercomposition yields a rubber sheet having an expansion factor of betweenabout 50 and 200 percent. After the fluxing processes are completed, theuncured rubber compound containing EPDM and the blowing agent isassembled with the pile yams and carrier layer as previously described.The vulcanization of the rubber backing sheet is then at least partiallyeffected within the press molding apparatus wherein the applied pressureis between 20 and 40 psi. Under the high temperatures and pressure, thenitrogen which is formed by the blowing agent partly dissolves in therubber. Due to the high internal gas pressure, small closed gas cellsare formed within the structure as the pressure is relieved upon exitfrom the press molding apparatus. In an alternative practice a post cureoven may be used to complete the vulcanization of the mat and provideadditional stability to the resulting product.

EXAMPLE

A rubber sheet material was produced by fluxing together the materialsas set forth in Table 1A in a standard rubber internal mixer at atemperature of about 280° F. to 300° F. for a period of one to twominutes. EPDM additions were varied as shown in Table 1A to yield ratiosof EPDM to NBR of 3.0 (75 parts EPDM to 25 parts NBR); 1.5 (60 partsEPDM to 40 parts NBR); and 1.0 (50 parts EPDM to 50 parts NBR).Additions of curative agents as provided in Table 1B were then made. AnUncured sheet of the fluxed rubber compounds was then calendared, placedover a die mold having a plurality of cylindrically configured openings,covered partially with a pile fabric component (attached to a carrierfabric) and cured at a temperature of about 290° F. for five (5) minutesunder a pressure of about 40 psi and post cured at a temperature ofabout 290° F. at atmospheric pressure for a period of five (5) minutes.The resultant floor covering article provided a significant amount ofincreased cushioning as compared to a sample article prepared withoutthe utilization of the die mold but with the same rubber composition andpile fabric covering and under the same conditions as the inventive mat.Furthermore, the inventive mat, when placed on a floor with theresultant foam rubber protrusions in contact with the floor exhibited asubstantial reduction in slip capability as compared with the standardnon-cleated foam rubber sample produced without the use of the diemolding vessel did not exhibit any appreciable carbon staining from therubber backing sheet.

While the invention has been described and disclosed in connection withcertain preferred embodiments and procedures, these have by no meansbeen intended to limit the invention to such specific embodiments andprocedures. Rather, the invention is intended to cover all suchalternative embodiments, procedures, and modifications thereto as mayfall within the true spirit and scope of the invention as defined andlimited only by the appended claims.

What we claim is:
 1. A method of forming a cushioned floor coveringarticle comprising the steps of (a) laying at least one rubber sheetoptionally comprising a blowing agent to form a closed-cell foam rubberstructure upon vulcanization on one side of a die having at least afirst and second side, wherein said die has portions thereof removed toallow for the entry of molten rubber, wherein said removed portions ofsaid die include openings within both of said first and second side, andwherein said die is comprised of a material which can withstandvulcanization temperatures and pressures; (b) laying a carrier fabrichaving a tufted pile surface extending from one side of the carrierfabric onto said at least one rubber sheet of step “a”, wherein the sideof said carrier fabric from which said tufted pile does not extend is incontact with said at least one rubber sheet; (c) optionally, placingsolid rubber reinforcing strips around at least one of the border edgesof the rubber sheet; and (d) subjecting the composite comprising the atleast one rubber sheet, the die, the carrier fabric, and the optionalreinforcing strips to vulcanization temperatures and pressures to (1)attach said at least one rubber sheet to the side of the carrier fabricfrom which the pile surface does not extend, and (2) to form at leastone integrated rubber protrusion through the removed portions of thedie.
 2. The method of claim 1 wherein said removed portions of said dieare substantially circular in shape on the surface of both of said firstand second sides of said die.
 3. The method of claim 1 wherein saidblowing agent is present within said at least one rubber sheet of step“a”.
 4. The method of claim 1 wherein said at least one solid rubberreinforcing strips of step “c” are present.
 5. The method of claim 1wherein said tufted pile surface extending from said carrier fabriccomprises yarns selected from the group consisting of nylon, polyester,cotton, wool, and any blends thereof.
 6. The method of claim 4 whereinsaid tufted pile surface extending from said carrier fabric comprisessolution-dyed nylon.
 7. The method of claim 1 wherein said carrierfabric is selected from the group of fabric materials consisting ofwoven fabrics, non-woven fabrics, and knit fabrics.
 8. A method offorming a cushioned floor covering article comprising the steps of (a)laying a first rubber sheet comprising solid rubber on one side of a diehaving at least a first and second side, wherein said die has portionsthereof removed to allow for the entry of molten rubber, and whereinsaid die is comprised of a material which can withstand vulcanizationtemperatures and pressures; (b) laying a second rubber sheet comprisingrubber and at least one blowing agent to form a closed-cell foam rubberstructure upon vulcanization on top of said first rubber sheet; (c)laying a carrier fabric having a tufted pile surface extending from oneside of the carrier fabric onto said second rubber sheet of step “b”,wherein the side of said carrier fabric from which said tufted pile doesnot extend is in contact with said second rubber sheet; (d) optionally,placing solid rubber reinforcing strips around at least one of theborder edges of either of said first or second rubber sheet or both; and(e) subjecting the composite comprising the first and second rubbersheets, the die, the carrier fabric, and the optional reinforcing stripsto vulcanization temperatures and pressures to (1) attach the two rubbersheets together, (2) attach said second rubber sheet to the side of thecarrier fabric from which the pile surface does not extend, and (3) toform at least one integrated rubber protrusion through the removedportions of the die, wherein said at least one integrated rubberprotrusion comprises a solid rubber cap over a foam rubber core.
 9. Themethod of claim 8 wherein said removed portions of said die aresubstantially circular in shape on the surface of both of said first andsecond sides of said die.
 10. The method of claim 8 wherein said atleast one solid rubber reinforcing strips of step “d” are present. 11.The method of claim 8 wherein said tufted pile surface extending fromsaid cailier fabric comprises yarns selected from the group consistingof nylon, polyester, cotton, wool, and any blends thereof.
 12. Themethod of claim 11 wherein said tufted pile surface extending from saidcarrier fabric comprises solution-dyed nylon.